双阴极MFC启动过程中的电化学特性

构建以污水处理厂二沉池污泥接种的双阴极微生物燃料电池（MFC），用循环伏安法（CV）、交流阻抗法（EIS）表征了MFC启动阶段的电化学特性。结果表明：经过3个周期的运行，输出电压稳定，反应器启动成功，启动阶段厌氧-好氧和厌氧-缺氧部分输出电压的最大值分别为175和336 mV。缺氧阴极，厌氧阳极电极生物膜CV检测中出现氧化还原峰，随着启动时间的增加，其峰值电流逐渐增大；而好氧阴极电极生物膜的CV检测结果中未出现明显的氧化还原峰。悬浮污泥的CV检测结果中出现了成对的氧化还原峰，表明生物代谢过程中有电子中介体产生。EIS结果说明电极的欧姆内阻和扩散内阻基本保持不变，极化内阻在不断减小，很好地反映了产电微生物在电极上富集的过程。启动成功后缺氧、厌氧和好氧电极的极化内阻值分别为2.86、2.33和57.64 Ω，好氧阴极极化内阻值较大，表明其电极生物膜催化能力较弱。

Electrochemical characterization of dual cathode MFC during start-up phase

In this study, the construction of the experiment was based on the double cathode microbial fuel cell (MFC), which was inoculated with the second sedimentation tank of sewage treatment plant.As for the start-up stage, the electrochemical characteristics of MFC were characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) methods. The results indicated that the output voltage is stable after three cycles of operation. Thus, the reactor is started successfully. And the maximum values are 175 and 336 mV, corresponding to anaerobic-aerobic and anaerobic-hypoxia for output voltages in the start-up phase. As for the CV method, the redox peaks can be clearly observed in the detection of the electrode biofilms of hypoxic cathodes and anaerobic anodes. In addition, the current of the peak increases gradually with the start-up time increases. However, there is no significant redox peak detected in the aerobic cathode biofilms. And the several pairs of redox peaks can be detected in the suspended sludge, which confirmed that the bio-metabolic processes produce electronic intermediates. According to the EIS method, the results shown that the ohmic resistance and diffusion resistance of the electrode remain unchanged. At the same time, its polarization resistance is reduced continuously which revealed well that microorganism enrichment process on electrodes. What's remarkable is the change of the polarization resistance of the electrode after the reactor is started successfully. Its values are 2.86 Ω (hypoxia),2.33 Ω (anaerobic) and 57.64 Ω (aerobic), respectively, in which the polarization resistance of the aerobic cathode was higher than others, indicating that its electrode biofilm catalytic ability is relatively weak.